Avoid complicated grammar rules which Arab people don't care about. And as "Eid" said, avoid e3rab too. In short, speak MSA the way Arab people speak it, which is the wrong way!

keep away from e3rab (thama , fat`ha, kasara). I assume that more than 99% of Arabs including those who can speak MSA, but not me ;) are not mastering that.

Find a native and speak with them while hanging out.

Sadia O, it's not about learning faster. The right question is are you ready to spend most of your time in learning? To learn you have to be patient. First of all, you have to speak with Arabian natives and I think italki is made for that reason, to help you to become more better in any language you want. There is an application called Rosetta Stone. I used lots of courses and applications in learning English. I assure you that Rosetta Stone is the best application I've ever used. Here's the link: http://www.rosettastone.com/

Don't listen to people says you must avoid Al-E'rab ! The grammar is a part of any language, and you must lean some to begin understand sentences and linking words.